Method of cementino wells



Much'24, 1936." E. v cRowELL n BTHOD 0F CHENTHG WELLS I orignm Filed laren 1. '1927 Reissued Mar. 24, 1936 UNITED 4STATES PATENT OFFICE ,RIETHOD F CEMENTING WELLS ErdV.Crowell,LooAngeles,Calif.`

Original application Mann 1, 1921, sei-m N. Divided and application January 10, 1929, serai Nn. 331.411.

Patent No. 1,828,100,

dated October 20, 1931. This application for reissue December 24, 1932, Serial No. 648,819

2 Claims. (01'. 16B-21) tion to permit the carrying on of drilling operapredetermined level, so that a subsequently introtions or the circulation of a washing medium through the bore of a string of casing in a Well and thence upwardly in the surrounding well bore, and of then forcing a cementing mixture downwardly through the bore of the casing lto any predetermined level and thence outwardly through the casing to lill the surrounding bore. In practice, it has been found advantageous to have the full bore, or substantially the full bore, of a string of casing available when carrying on drilling operations or washing down the string of casing, and it is also desirable when circulating a washing medium preparatory to ya cementing operation to utilize the bore of the casing, which should'not be substantially impeded or restricted, and then to supply the cementing mixture through the unobstructed bore of the casing, or, at least, through a bore of the casing not restricted or obstructed to such an extent as to seriously impede orprevent the operation referred-to,` and to then discharge said cementing mixture at any predetemined level.

It is therefore a particular object of the present invention to provide for the flow of a circulating medium downwardly through the well casing and thence upwardly in the surrounding well bore.

preferably by discharging the washing medium outwardly through the casing at the predetermined level at which the .cementing mixture is adapted for subsequent discharge, but such discharge of circulating medium may be through the bottom of the casing, when said casing is not resting on a formation seat and when there is no other obstruction to securing circulation though the bottom of the casing. and it may be through peripheral ports in the casing when bottom circulation is impeded or prevented in any way or when the casing is resting on the formation seat, the present method being adaptable to all conditions which may be met in the cementing operation.

A plug, which is lowered in the casing accompanying or following the washing medium, may then be anchored immediately below peripheral ports, which vare provided in the casing at any duced cementing mixture ows downwardly through the bore of the casing to the anchored plug; but is then prevented from flowing downwardly through the casing below the plug and is consequently discharged through the peripheral ports into the surrounding well bore.

It is a further object of the invention to force a traveling plug downwardly through the substantially unobstructed bore of the well casing in back of the quantity of cement which is to be discharged into the surrounding well bore, soas to force the cement through the peripheral ports of the well casing, and to then arrest the traveling plug by seating it on the anchored plug, so that its upper portion is above the peripheral ports in the casing, and thus indicate that all of the cement has been forced through the peripheral ports into the surrounding bore and to also permit the closure of `the peripheral ports. against back flow of the cement into the bore of the casing.

'I'he invention will be readily understood from the following description of the accompanying drawing, in which:

Fig. 1 is a vertical section through a well bore showing a string of casing, partly in axial section, and adapted for circulation of a washing medium prior to the cementing operation.

sectiononthelinel-l of casing, which has a substantially unobstructed bore I forming a continuation of the uniform bore of the string. is D IOvlded with peripheral ports l. The ports 4 may be normally closed by spring pressed valves 5, but these valves are adapted to open responsive to pressure in the casing so as to permit discharge of material into the surrounding well bore.

Below the ports 4 of the bore of the ported section of the casing preferably has an increased diameter forming an elongated annular recess 1 terminating in upper and lower shoulders 8 and 9 formed by continuations of the uniform bore of the string of casing; and the lower shoulder 9 forms a seat for a plug I0 adapted for expansion u 2. into recess 1, while the upper shoulder l is preferably inclined to permit ready expansion of the plug when'it is lowered through the bore of the casing to the level of the recess. l

In order to provide anchoring means for plug I0 in recess 1, the plug'is shown as provided with an intermediate reduced diameter -Il adapted to receive arcuate locking slips i2 which are adapted to contract wholly within the outer periphery of the plug. Bias springs I3 fixed to the plug in back of the slips engage the latter so as to tend to expand the same beyond the periphery of the plug, and expansion of the slips is preferably guided and limited by abutments Il on the plug engaging in notches i5 in the slips. As the plug is lowered through casing A, the uniform bore of the latter contracts the slips to permit free passage of the plug, and when the plug is opposite recess 1. the annular enlargement formed therebypermitssprings Iltoexpandtheslipssothat they rest on the shoulder 9 and thereby anchor the plug.

Packing is preferably mounted on the plug to insure a tight shutting oil! of the casing when the plug is anchored in recess 1, the parts being so arranged that when the plug is anchored its packing closes the bore of the casing Just below ports l. As aconsequence, a cementing mixture introduced into the well casing above the anchored plug is prevented from flowing down the casing past the plug and thereby forces valves 6 open for discharge of the cement through the ports 4 into the surrounding well bore. A

A predetermined supply of the cementing mixtureisprei'erably thus discharged through ports 4, the quantity of cement being by a traveling plug II lowered in the well casing in back of the cementing mixture. 'I'he traveling plug slides freely in the uniform bore of the casing and is preferably provided with packing to prevent leakage of the cementing material past the plug.

The lower ends of plugs vlo and Il are preferably tapered as shown at i1 to guide the plugs through the bore of the casing, and the packing for the plugs may be mounted on annular shoulders Il formed at the upper ends of the plugs by reducing their diameter as -shown at I l. 'Ihe packing is preferably annular lcup-packing Il snugly the casing wall and fixed against shoulders Il by followers flvwhich may be held in place by pins 22.

In operation, the section of the string of casing lwhichisprovided with portslgandrecel may formashoefaatthelowerendofthestringof casing,andthestringofcasingthuspresentsa .uniform bore without any substantial obstruction pror to the lowering ofplug lo, with ports 4 closed by their spring-seated valves I. The casing may be washed down or drilling may be continued through the casing. the substantially open bore permitting freedom of such operations: and when itisdesiredtocirculateawashingmedium,the casing preferably rests upon the formation seat. as shown in Iiig. i, sothatthe washing fluid forced downwardly through the casing will open valves l and thus ilow outwardly through the portsandupwardlyinthesurroundingbore.al though if it is preferred, and is feasible in any instance, the casing may be raised from its formation seat and circulation established through the bottom of the casing which maybelaterloweredifdesired, andthecirculation continued through said ports.

The washing medium may be forced downwardly through the casing by the plug I0 being A lowered through the casing in back of the wash- .ing medium, the plug being preferably forced downwardly by a cementing mixture introduced into the casing above the plug, until the plug automaticallyanohors in recess 1l immediately below ports! ,and thus shuts ofi4 the bore of the casing `below the ports, as shown in Fig. 2.

'I'he desired quantity of the cementing mixture is accurately measured by lowering the plug It into the casing in back of the predetermined quantity of cement, as shown in Fig. 2. the plug I6 being forced downwardly against the cementing mixture by a suitable fluid so that the pressure opens valves 5 for discharge of the cementing material through the ports I and into the surrounding well bore.

When all of the cement is discharged, plug I. is arrested by abutment against anchored plug Il, thereby indicating that the cementing operation is completed; and with the parts in this position, the cement is prevented from back flow into the casing, not only by the closing of valves 5, but also by the plug i6 closing the bore of the casing to ports I.

I have thus provided for drilling operations or circulating of a washing medium through a substantially open casing bore, with subsequent automatic anchoring of a plug in the bore, and fiow of cementing material downwardly through the bore of the casing until itis stopped by the plug. and thence outwardly through the casing to nil the surrounding well bore.

While I have in the above specication specili- -calLv disclosed and described a single practical method for stopping or anchoring the plug below peripheral ports without obstructing the casing. it will be quite obvious to those of skill in this art that various other means. perhaps creating slight and more or less immaterial obstructions or restrictions in the casing, may be devised, all, however, maintaining a bore in the' casing sufciently open for practical purposes and therefore without departing from the spirit of my invention.

I claim:

l. 'I'he method of cementing wells, which consists of: first, closing the bore of a normally substantially open well-casing at a predetermined point intermediate its upper and lower ends by means of a traveling plug inserted near the top of the casing and forced by fluid pressure downwardly through said casing and stopped at a predetermined point by means attached to the casing and relatively immovable with respect thereto: second, opening, by the pressure of circulating fluid from the top of the well normally springclosed ports located in said casing above said predetermined point of casing-bore closure; third. forcing pressure fluid downwardly through said casing and outwardly through-said ports; fourth,

forcing, by pump pressure from the top of the through'a well casing and through the' annular spsce outside of the casing: second, inserting in its upper portion a plug carrying means closely but slidingly ntting said casing; third. forcing aliquld eementing mixture into said casing above said plug and downwardly through said casing carrying and advancing said plug; fourth. closing the bore oi' said casing by the stopl'page oi" said plug by means within said casing and ilxed relatively thereto. at a predetermined point intermediate the upper and lower ends Vof said casing; ni'th, continuing the application otV fluid m pressurei'x'omthetopofthewellta:i'oroeopeu` normsllvolosedportsinsaidcasingabove predetermined point of closure and to torce cementin'g uld outwardly through said po into the annular space outside of the sixth, releasing pressure from the top of the weil topermit valves controlling said ports to close.

thus preventing the cement in the annular space outside of the casing from flowing back into the casing; f

ERD V. CROWELL. 

